York YSCD, Manual, Page: 34 / 108

34
Belt Tension
Adjust the belt tension if necessary.
Required belt
tension data is listed in Table 11 below . Never use
belt dressing on the belts. If belts slip with the proper
tension, use a good grade belt cleanser to clean the
belts.
Never use excessive belt tension,
as this could re sult in damaging
the bear ing, motor pul leys or mo tor
base. See drive label on fan housing
adjacent to drive for spe cifi c de tails
on ten sion.
When it is necessary to replace one belt in a given set,
the entire set of belts must be replaced.
PERIODIC MAINTENANCE – YEARLY
Check the fan wheel and inspect the drain pans for
sludge and foreign material. Clean if required.
If unit has an air side economizer, observe the operation
of all dampers and make any necessary adjustments in
linkage and blade orientation for proper operation.
Entire Unit Inspection
In addition to the checks listed in this sec tion, pe ri od ic
over all inspections of the unit should be ac com plished to
en sure proper equipment operation. Items such as loose
hardware, component operation, un usu al noises, etc.
should be investigated and cor rect ed immediately.
Sheave Alignment
To check sheave alignment, a straight edge or a piece of
string can be used. If the sheaves are properly aligned,
the string or straight edge will touch at all points,
as
in di cat ed in Fig. 3. Rotating the sheaves will de ter mine
if the sheave is wobbly or the drive shaft is bent.
Align ment error must be corrected to avoid bear ing
and belt failure.
Belts
New belts should be re-checked after 24 hours of
operation. On multiple belt adjustable pul leys, the pitch
depth should be checked to insure iden ti cal belt trav el,
power transfer and wear. Adjustable motor bases are
pro vid ed for belt adjustment.
Motor pulleys and blower shaft pulleys are locked
in po si tion with ei ther set screws or split taper lock
bush ings. All set screws and/or taper lock bolts must
be checked for tightness and align ment be fore put ting
equip ment into op er a tion.
TABLE 11 – BELT TENSION DATA
BELT CROSS
SECTION
SMALLEST SHEAVE
DIAMETER RANGE
RPM RANGE
BELT DEFECTION FORCE
SUPER GRIPBELTS AND UN-
NOTCHED GRIPBANDS
GRIPNOTCH BELTS AND NOTCHED
GRIPBANDS
USED BELTS NEW BELTS USED BELTS NEW BELTS
5V, 5VX
4.4 - 6.7
550 - 1749
1750 - 3000
3001 - 4000
-
-
-
-
-
-
10.2
8.8
5.6
15.2
13,2
8.5
7.1 - 10.9
500 - 1740
1741 - 3000
12.7
11.2
18.9
16.7
14.8
13.7
22.1
20.1
11.8 - 16.0
500 - 1740
1741 - 3000
15.5
14.6
23.4
21.8
17.1
16.8
25.5
25.0
SHEAVE DIAMETER – INCHES; DEFLECTION FORCE - LBS
FIG. 3 – SHEAVE ALIGNMENT
LD07634
CORD TOUCHING SHEAVES AT
POINTS INDICATED BY AR ROWS
CORD TIED
TO SHAFT
Maintenance
JOHNSON CONTROLS
FORM 145.05-NOM2 (807)